Laser light therapy could be the key to improving short-term memory

"People with conditions like ADHD (attention deficit hyperactivity disorder) or other attention-related conditions could benefit from this type of treatment, which is safe, simple, and non-invasive, with no side effects," said Dongwei Li, a visiting Ph.D. student at the University of Birmingham’s Center for Human Brain Health, and co-author of the paper, in the press release.

Researchers from Beijing Normal University conducted clinical trials on 90 participants between the ages of 18 and 25. While some participants received the treatment of laser light at wavelengths of 1064 nm to the right prefrontal cortex, the others were treated at a shorter wavelength, or the treatment was delivered to the left prefrontal brain. To eliminate the placebo effect, each participant was also given a sham or inactive tPBM.

The participants were later asked to recall the orientations or colors of a series of objects exhibited on a screen after receiving tPBM treatment for more than 12 minutes. Those who received the laser light to the right prefrontal cortex of their brain at 1064 nm demonstrated better improvements compared to the participants who received the treatment in receiving other variations.

Further research is still needed to gain more insight

The reasons why the treatment's beneficial benefits on working memory and how long those effects will last are still unknown to the researchers. Further research is needed to gain insight into these topics.

“We need further research to understand exactly why the tPBM is having this positive effect, but it’s possible that the light is stimulating the mitochondria – the powerplants – in the nerve cells within the prefrontal cortex, and this has a positive effect on the cells’ efficiency," said Professor Ole Jensen, also at the Centre for Human Brain Health.

"We will also be investigating how long the effects might last. Clearly, if these experiments are to lead to a clinical intervention, we will need to see long-lasting benefits.”

The study was published in Science Advances on December 2.

Abstract:

Transcranial photobiomodulation (tPBM) is a safe and noninvasive intervention that has shown promise for improving cognitive performance. Whether tPBM can modulate brain activity and thereby enhance working memory (WM) capacity in humans remains unclear. In this study, we found that 1064-nm tPBM applied to the right prefrontal cortex (PFC) improves visual working memory capacity and increases occipitoparietal contralateral delay activity (CDA). The CDA set-size effect during retention mediated the effect between the 1064-nm tPBM and subsequent WM capacity. The behavioral benefits and the corresponding changes in the CDA set-size effect were absent with tPBM at a wavelength of 852 nm or with stimulation of the left PFC. Our findings provide converging evidence that 1064-nm tPBM applied to the right PFC can improve WM capacity.